Stacking device for flat stackable elements

ABSTRACT

A stacking device includes a movable stacking wall and a further stacking wall between which flat stackable elements are adapted to be stacked. An impact wall defines the path of insertion for a stackable element newly introduced between the stacking walls. The movable stacking wall is impinged by a restoring element with a restoring force in the direction of the further stacking wall. A braking element partially converts the kinetic energy of the movable stacking wall to thermal energy independent of the position thereof.

[0001] The present invention relates to a stacking device for flat stackable elements, having a movable and a further stacking wall between which the stackable elements can be stacked, and an impact wall, by means of which a path of insertion for a stackable element newly introduced between the stacking walls is defined, the movable stacking wall being acted upon by means of a restoring element with a restoring force in the direction of the further stacking wall.

[0002] Stacking devices of this type are known. They are used, in particular, in automated distribution systems for letters and items of mail resembling letters. Beginning at the stacking wall facing the conveying section, the stack grows along the impact wall. The aim is a geometrically precise stack even in the case of heavy and thick items.

[0003] The items are introduced into the stacking device at a relatively high conveying speed. The speeds are up to 5 meters per second. With heavy and thick items, faults occur due to rebound from the impact wall and/or excessive deflection of the movable stacking wall.

[0004] In the prior art, it is known, in addition to the retracting spring, also to use a movement-damping means by latching the movable stacking wall longitudinally into place. It is also known to provide the movable stacking wall with a soft coating. However, the two measures do not result in the desired properties particularly if the stacking compartment is empty or only filled to a small extent and especially if relatively thick and heavy items follow one another.

[0005] The object of the present invention is to develop a stacking device of the type mentioned at the beginning in such a manner that even when the stacking device is empty or only filled to a small extent, reliable operation of the stacking device is possible irrespective of the weight of the stackable elements.

[0006] The object is achieved by the movable stacking wall being assigned a braking element, by means of which kinetic energy of the movable stacking wall can be partially converted into thermal energy irrespective of the position of said wall.

[0007] If the braking element is designed in such a manner that the kinetic energy of the movable stacking wall can essentially be converted into thermal energy only if it moves away from the further stacking wall, the movable stacking wall is returned again more rapidly into its starting position.

[0008] If the braking element is designed in such a manner that the amount of kinetic energy of the movable stacking wall that is converted into thermal energy increases with increasing acceleration of the movable stacking wall, the stacking device operates particularly reliably.

[0009] If the movable and the further stacking wall form an opening angle of between 0° and 30°, an easy introduction of newly arriving stackable elements is ensured.

[0010] If the restoring element is designed as a spring-loaded coiling drum for a sheathed cable, said coiling drum being connected to the movable stacking wall by means of the sheathed cable, the restoring element is of structurally simple construction and requires only a small amount of structural space.

[0011] If the sheathed cable forms a single-layered coil on the coiling drum, the stacking device operates in a particularly operationally reliable and fault-free manner. In particular, the sheathed cable cannot become jammed.

[0012] If the sheathed cable is wound conically on the coiling drum, the coupling between the restoring element and movable stacking wall can be varied as required in a simple manner.

[0013] If the coiling drum is mounted displaceably in the direction of the sheathed cable originating from the coiling drum and the coiling drum is assigned at least one brake shoe which, on movement of the movable stacking wall away from the further stacking wall, can be positioned at a braking region, it can be achieved, in a structurally simple manner, that the kinetic energy of the movable stacking wall can essentially be converted into thermal energy only on movement away from the further stacking wall.

[0014] If the brake shoe is designed as a leading brake shoe, a self-energizing braking action is produced.

[0015] If the coiling drum is mounted rotatably about a drum point of rotation, the brake shoe is mounted pivotably about a pivot point, and a section connecting the pivot point in the drum point of rotation runs parallel to the displacement direction of the coiling drum, a particularly advantageous interaction of coiling drum and brake shoe is produced.

[0016] The brake shoe can be arranged over fixing position or on the coiling drum. If, in the latter case, the brake shoe is mounted and designed in such a manner that, when the coiling drum rotates, it automatically positions itself at the braking region owing to the centrifugal force, the centrifugal force can be used for positioning the brake shoe at the braking region.

[0017] If the brake shoe is coated with a compressible lining, for example felt or leather, and/or the braking region consists of a material which does not change under the effect of air, for example of smoothly polished brass or plastic, a braking action which can be proportioned particularly gently is produced.

[0018] Further advantages and details emerge from the following description of an exemplary embodiment in conjunction with the drawings, in which, in a basic illustration

[0019]FIG. 1 shows a stacking device from above,

[0020]FIG. 2 shows the stacking device of FIG. 1 from the front,

[0021]FIG. 3 shows a coiling drum from the side,

[0022]FIG. 4 shows the coiling drum of FIG. 3 from the opposite side, and

[0023]FIG. 5 shows the coiling drum of FIG. 3 from above.

[0024] According to FIG. 1, a stacking device has a movable stacking wall 1 and a further, fixed stacking wall 2. The movability of the movable stacking wall 1 is indicated in FIGS. 1 and 2 by a double arrow A. Flat stackable elements 3, 4 can be stacked between the stacking walls 1, 2. The stackable elements 3, 4 may, for example, be letters. According to FIG. 1, the stackable elements 3 being stacked and the stackable element 4 is being newly supplied to the stack.

[0025] The stackable element 4 is supplied to the stack by the stackable element 4 being “shot” into the stack at an introducing speed v in an introducing direction x. The introducing speed v is up to 5 meters per second. The stacking device therefore also has an impact wall 5, by means of which a path of insertion for the stackable element 4 newly introduced between the stacking walls 1, 2 is defined.

[0026] For easy introduction of the stackable element 4, the stacking walls 1, 2 form an opening angle α. The opening angle α lies between 0° and 30°, for example between 10° and 20°.

[0027] When the stackable element 4 is introduced, the movable stacking wall 1 springs open counter to a restoring force F and afterward springs back again into its starting position. The movable stacking wall 1 is thus acted upon with the restoring force F in the direction of the fixed stacking wall 2. The restoring force F is applied by a restoring element 6 which is connected to the movable stacking wall 1 via a sheathed cable 7.

[0028] According to FIGS. 3-5, the restoring element 6 is designed as a spring-loaded coiling drum 6 for the sheathed cable 7. The sheathed cable 7 forms a single-layered coil on the coiling drum 6. This can be seen particularly clearly from FIG. 5.

[0029] According to FIG. 5, the coiling drum 6 is of cylindrical design. The coiling drum 6 could, however, also have a conical profile, as indicated in FIG. 5 by dashed or dash-dotted lines. In this case, the sheathed cable 7 would be coiled conically on the coiling drum 6. By appropriate design of the coiling drum 6, the coupling between the movable stacking wall 1 and the coiling drum 6 can therefore be varied as required.

[0030] The restoring element 6 serves not only for restoring the movable stacking wall 1, but at the same time is also designed as a braking element 6. The coiling drum 6 is thus able to convert kinetic energy of the movable stacking wall 1 into thermal energy irrespective of the position of said wall, insofar as this energy is not reversibly absorbed by a restoring spring 8. The restoring spring 8 is illustrated, in particular, in FIG. 4.

[0031] In order to apply the braking action, the coiling drum 6 is assigned a brake shoe 9. A single brake shoe 9 is illustrated here in FIG. 3. However, there could also be a plurality of brake shoes 9, if appropriate.

[0032] The brake shoe 9 is mounted pivotably about a pivot point 10. It is positioned at a braking region 12 of the coiling drum 6 by means of a compression spring 11. The pivot point 10 is positionally fixed, i.e. it does not rotate together with the coiling drum 6 on rotation of the latter. The compression spring 11 may be designed, if appropriate, in a manner such that it can be adjusted. The brake shoe 9 is coated with a compressible lining 13. The lining 13 may, for example, be felt or leather. The braking region 12 consists of a material which does not change under the effect of air. Suitable materials are, in particular, smoothly polished brass or plastic.

[0033] Owing to the structural design of the brake shoe 9 and to the arrangement of the pivot point 10, the brake shoe 9 is designed as a leading brake shoe 9. It therefore shows a self-energizing braking action when the movable stacking wall 1 is deflected and when said wall springs back, the brake shoe is released again from the braking region 12. It is thus positioned at the braking region 12 during the movement of the movable stacking wall 1 away from the fixed stacking wall 2. Owing to these braking properties, the kinetic energy of the movable stacking wall 1 is essentially converted into thermal energy only if it moves away from the fixed stacking wall 2.

[0034] The coiling drum 6 is mounted rotatably about a drum point of rotation 14. In this case, the coiling drum 6 has a clearance. It is therefore mounted displaceably in the direction of the sheathed cable 7 originating from the coiling drum 6. The displacement direction is indicated in FIG. 3 by y. As is apparent, the displacement direction y runs parallel to a section which connects the pivot point 10 and the drum point of rotation 14. The effect achieved by this design is that the amount of kinetic energy of the movable stacking wall 1 that is converted into thermal energy increases with increasing acceleration of the movable stacking wall 1. This is because the greater an impulse which acts on the movable stacking wall 1, the more firmly is the brake shoe 9 positioned at the braking region 12. An increased braking action is therefore produced, which, according to the invention is desirable.

[0035] According to FIGS. 3-5, the brake shoe 9 is mounted in a positionally fixed manner, i.e. it does not rotate together with the coiling drum 6, but is merely positioned on the latter. However, it is also possible to arrange the brake shoe 9 on the coil drum 6 itself and to position it at a fixed braking region 12. In this case, it is possible, in particular, to mount and design the brake shoe 9 in such a manner that, when the coiling drum 6 is rotated, said brake shoe automatically positions itself at the braking region 12 owing to the centrifugal force. 

1. A stacking device for flat stackable elements (3, 4), having a movable and a further stacking wall (1, 2) between which the stackable elements (3, 4) can be stacked, and an impact wall (5), by means of which a path of insertion for a stackable element (4) newly introduced between the stacking walls (1, 2) is defined, the movable stacking wall (1) being acted upon by means of a restoring element (6) with a restoring force (F) in the direction of the further stacking wall (2), characterized in that the movable stacking wall (1) is assigned a braking element (6), by means of which kinetic energy of the movable stacking wall (1) can be partially converted into thermal energy irrespective of the position of said wall.
 2. The stacking device as claimed in claim 1, characterized in that the braking element (6) is designed in such a manner that the kinetic energy of the movable stacking wall (1) can essentially be converted into thermal energy only if it moves away from the further stacking wall (2).
 3. The stacking device as claimed in claim 1 or 2, characterized in that the braking element (6) is designed in such a manner that the amount of kinetic energy of the movable stacking wall (1) that is converted into thermal energy increases with increasing acceleration of the movable stacking wall (1).
 4. The stacking device as claimed in claim 1, 2 or 3, characterized in that the movable and the further stacking wall (1, 2) form an opening angle (α) of between 0° and 30°.
 5. The stacking device as claimed in one of the above claims, characterized in that the restoring element (6) is designed as a spring-loaded coiling drum (6) for a sheathed cable (7), said coiling drum being connected to the movable stacking wall (1) by means of the sheathed cable (7).
 6. The stacking device as claimed in claim 5, characterized in that the sheathed cable (7) forms a single-layered coil on the coiling drum (6).
 7. The stacking device as claimed in claim 5 or 6, characterized in that the sheathed cable (7) is coiled conically on the coiling drum (6).
 8. The stacking device as claimed in claim 5, 6 or 7, characterized in that the coiling drum (6) is mounted displaceably in the direction (y) of the sheathed cable (7) originating from the coiling drum (6).
 9. The stacking device as claimed in one of claims 5 to 8, characterized in that the coiling drum (6) is assigned at least one brake shoe (9) which, on movement of the movable stacking wall (1) away from the further stacking wall (2), can be positioned at a braking region (12).
 10. The stacking device as claimed in claim 9, characterized in that the brake shoe (9) is designed as a leading brake shoe (9).
 11. The stacking device as claimed in claim 8 and 9 or 8 and 10, characterized in that the coiling drum (6) is mounted rotatably about a drum point of rotation (14), in that the brake shoe (9) is mounted pivotably about a pivot point (10), and in that a section connecting the pivot point (10) and the drum point of rotation (14) runs parallel to the displacement direction (y) of the coiling drum (6).
 12. The stacking device as claimed in claim 9 or 10, characterized in that the brake shoe (9) is arranged on the coiling drum (6).
 13. The stacking device as claimed in claim 12, characterized in that the brake shoe (9) is mounted and designed in such a manner that, when the coiling drum (6) is rotated, it automatically positions itself at the braking region (12) owing to the centrifugal force.
 14. The stacking device as claimed in one of claims 9 to 13, characterized in that the brake shoe (9) are coated with a compressible lining (13), for example felt or leather.
 15. The stacking device as claimed in claim 14, characterized in that the braking region (12) consists of a material which does not change under the effect of air, for example smoothly polished brass or plastic. 